str = "day up day"
for i in range(len(str)):
    print(str[i],end=" ")

list1=[]
list1[0] = 1
list1[1] = 2
list1.append(3)
print(list1)

list2 = [1,2,3]

list3 =list();
list3.append(1)
list3.append(2)
list3.append(3)
print(list3)



list2 = [1,2,3]
for i in list2:
    print(i)
list2.insert(1,10)
print(list2)
list2.extend([11,11])
print(list2)
list2.sort(reverse=True)#默认升序
print(list2)

list3 = sorted(list2)
print(list2)
print(list3)

del list3
print(list3)
list4=[1,3,5,7,9]

list5 = [i**2 for i in range]
